package com.hmdp.utils;

import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.format.annotation.DateTimeFormat;
import org.springframework.stereotype.Component;

import javax.annotation.Resource;
import java.time.LocalDateTime;
import java.time.ZoneOffset;
import java.time.format.DateTimeFormatter;


/**
 * redis全局唯一id生成器
 */
@Component
public class RedisIdWorker {
    /**
     * 开始时间戳，2022/1/1 00：00：00
     */
    private static final long BEGIN_TIMESTAMP = 1640995200L;

    @Resource
    private StringRedisTemplate stringRedisTemplate;

    /**
     * 序列号的位数32位
     */
    private static final int COUNT_BITS = 32;

    public long nextId(String keyPrefix){
        //1.生成时间戳
        LocalDateTime now = LocalDateTime.now();
        long nowSecond = now.toEpochSecond(ZoneOffset.UTC);
        long timestamp = nowSecond - BEGIN_TIMESTAMP;

        //2.生成序列号
        //2.1.获取当前日期，精确到天
        String data = now.format(DateTimeFormatter.ofPattern("yyyy:MM:dd"));
        System.out.println(data);
        //2.2.自增长
        long count = stringRedisTemplate.opsForValue().increment("icr:" + keyPrefix + ":" + data);

        //3.拼接并返回
        return timestamp << COUNT_BITS | count;

    }
}
